/*
 * JScroll - the scrollable desktop pane for Java.
 * Copyright (C) 2003 Tom Tessier
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 */

package org.jscroll.widgets;

import javax.swing.*;

import java.awt.*;


/**
 * This class provides the scrollpane that contains the virtual desktop.
 *
 * @author <a href="mailto:tessier@gabinternet.com">Tom Tessier</a>
 * @version 1.0  11-Aug-2001
 */
public class DesktopScrollPane extends JScrollPane {
    private DesktopMediator desktopMediator;
    private RootDesktopPane desktopPane;
    private FramePositioning positioning;

    /**
     * creates the DesktopScrollPane object
     *
     * @param desktopMediator a reference to the DesktopMediator object
     */
    public DesktopScrollPane(DesktopMediator desktopMediator) {
        this.desktopMediator = desktopMediator;

        desktopPane = new RootDesktopPane(this);
        setViewportView(desktopPane);

        positioning = new FramePositioning(this);

        // set some defaults
        setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
        setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);

        // set scrollbars to scroll by 5 pixels each...
        getHorizontalScrollBar().setUnitIncrement(5);
        getVerticalScrollBar().setUnitIncrement(5);
    }

    /**
     * creates a JScrollInternalFrame and adds it to the virtual desktop
     *
     * @param dListener a reference to the DesktopListener
     * @param title the title displayed in the title bar of the internal frame
     * @param icon the icon displayed in the title bar of the internal frame
     * @param frameContents the contents of the internal frame
     * @param isClosable <code>boolean</code> indicating whether internal frame
     *          is closable
     * @param x x coordinates of internal frame within the scrollable desktop.
     *    <code>-1</code> indicates the virtual desktop is to determine the position
     * @param y y coordinates of internal frame within the scrollable desktop
     *    <code>-1</code> indicates the virtual desktop is to determine the position
     *
     * @return the JScrollInternalFrame that was created
     */
    public JScrollInternalFrame add(DesktopListener dListener, String title,
        ImageIcon icon, JPanel frameContents, boolean isClosable, int x, int y) {
        JScrollInternalFrame f = new JScrollInternalFrame(title, icon,
                frameContents, isClosable);
        f.addComponentListener(dListener);

        initAndAddFrame(f, x, y);

        return f;
    }

    /**
     * adds an internal frame to the virtual desktop
     *
     * @param dListener a reference to the DesktopListener
     * @param f the internal frame to add
     * @param x x coordinates of internal frame within the scrollable desktop.
     *    <code>-1</code> indicates the virtual desktop is to determine the position
     * @param y y coordinates of internal frame within the scrollable desktop
     *    <code>-1</code> indicates the virtual desktop is to determine the position
     */
    public void add(DesktopListener dListener, JInternalFrame f, int x, int y) {
        f.addComponentListener(dListener);
        initAndAddFrame(f, x, y);
    }

    /**
     * initializes the frame for display and adds it to the desktop
     *
     * @param f the internal frame to add
     * @param x x coordinates of internal frame within the scrollable desktop.
     *    <code>-1</code> indicates the virtual desktop is to determine the position
     * @param y y coordinates of internal frame within the scrollable desktop
     *    <code>-1</code> indicates the virtual desktop is to determine the position
     */
    private void initAndAddFrame(JInternalFrame f, int x, int y) {
        // override the position of this window? 
        if ((x != -1) && (y != -1)) {
            f.setLocation(x, y);
        } else {
            if (!getAutoTile()) {
                f.setLocation(cascadeInternalFrame(f));
            }
        }

        desktopPane.add(f);

        // select the newly added frame (note that must select it AFTER it
        // has been added to the desktopPane)
        try {
            f.setSelected(true);
        } catch (java.beans.PropertyVetoException e) {
            // swallow property veto exceptions here..!!
        }

        // resize desktop when add a frame in case any frames off screen
        resizeDesktop();
    }

    /**
     * returns all internal frames placed upon the virtual desktop
     *
     * @return a JInternalFrame array containing references to the internal frames
     */
    public JInternalFrame[] getAllFrames() {
        return desktopPane.getAllFrames();
    }

    /**
     * returns the internal frame currently selected upon the
     * virtual desktop
     *
     * @return a reference to the active JInternalFrame
     */
    public JInternalFrame getSelectedFrame() {
        return desktopPane.getSelectedFrame();
    }

    /**
     * closes the internal frame currently selected upon the
     * virtual desktop
     */
    public void closeSelectedFrame() {
        JInternalFrame f = getSelectedFrame();

        if (f != null) {
            f.doDefaultCloseAction();
        }
    }

    /**
     * selects the specified internal frame upon the virtual desktop
     *
     * @param f the internal frame to select
     */
    public void setSelectedFrame(JInternalFrame f) {
        try {
            JInternalFrame currentFrame = desktopPane.getSelectedFrame();

            if (currentFrame != null) {
                currentFrame.setSelected(false);
            }

            f.setSelected(true);
            f.setIcon(false); // de-iconify it (if iconified)
        } catch (java.beans.PropertyVetoException pve) {
            System.out.println(pve.getMessage());
        }
    }

    /**
     *  flags the specified internal frame as "contents changed." Used to
     * notify the user when the contents of an inactive internal frame
     * have changed.
     *
     * @param f the internal frame to flag as "contents changed"
     */
    public void flagContentsChanged(JInternalFrame f) {
        if (desktopPane.getSelectedFrame() != f) {
            RootToggleButton button = (RootToggleButton) ((JScrollInternalFrame) f).getAssociatedButton();
            button.flagContentsChanged(true);
        }
    }

    /**
     * selects the next available frame upon the virtual desktop
     */
    public void selectNextFrame() {
        JInternalFrame[] frames = getAllFrames();

        if (frames.length > 0) {
            try {
                frames[0].setSelected(true);
            } catch (java.beans.PropertyVetoException pve) {
                System.out.println("Bean veto: " + pve.getMessage());
            }
        }
    }

    /**
     * returns the number of internal frames upon the virtual desktop
     *
     * @return an <code>int</code> representing the number of internal frames
     */
    public int getNumberOfFrames() {
        return desktopPane.getComponentCount();
    }

    /**
     * sets the preferred size of the virtual desktop
     *
     * @param dim a Dimension object representing the desired preferred size
     */
    public void setDesktopSize(Dimension dim) {
        desktopPane.setPreferredSize(dim);
        desktopPane.revalidate();
    }

    /**
     * returns the preferred size of the virtual desktop
     *
     * @return a Dimension object representing the current preferred size
     */
    public Dimension getDesktopSize() {
        return desktopPane.getPreferredSize();
    }

    /////
    // positioning methods
    /////

    /**
     * propogates setAutoTile to FramePositioning
     *
     * @param autoTile <code>boolean</code> representing autoTile mode.
     *      If <code>true</code>, then all new frames are tiled automatically.
     *      If <code>false</code>, then all new frames are cascaded automatically.
     */
    public void setAutoTile(boolean autoTile) {
        positioning.setAutoTile(autoTile);
    }

    /**
     * propogates getAutoTile to FramePositioning
     *
     * @return <code>boolean</code> representing current autoTile mode
     */
    public boolean getAutoTile() {
        return positioning.getAutoTile();
    }

    /**
     * propogates cascadeInternalFrame to FramePositioning
     *
     * @param f the internal frame to cascade
     *
     * @return a Point object representing the position of the internal frame
     */
    public Point cascadeInternalFrame(JInternalFrame f) {
        return positioning.cascadeInternalFrame(f);
    }

    /**
     * propogates cascadeInternalFrames to FramePositioning
     */
    public void cascadeInternalFrames() {
        positioning.cascadeInternalFrames();
    }

    /**
     * propogates tileInternalFrames to FramePositioning
     */
    public void tileInternalFrames() {
        positioning.tileInternalFrames();
    }

    /**
     * centers the viewport of the virtual desktop around the
     *   provided internal frame
     *
     * @param f the internal frame to center the viewport about
     */
    public void centerView(JScrollInternalFrame f) {
        // set the view centered around this item
        Rectangle viewP = getViewport().getViewRect();
        int xCoords = (f.getX() + (f.getWidth() / 2)) - (viewP.width / 2);
        int yCoords = (f.getY() + (f.getHeight() / 2)) - (viewP.height / 2);

        Dimension desktopSize = getDesktopSize();

        if ((xCoords + viewP.width) > desktopSize.width) {
            xCoords = desktopSize.width - viewP.width;
        } else if (xCoords < 0) {
            xCoords = 0;
        }

        if ((yCoords + viewP.height) > desktopSize.height) {
            yCoords = desktopSize.height - viewP.height;
        } else if (yCoords < 0) {
            yCoords = 0;
        }

        getViewport().setViewPosition(new Point(xCoords, yCoords));
    }

    /**
     * resizes the virtual desktop based upon the locations of its
     * internal frames. This updates the desktop scrollbars in real-time.
     * Executes as an "invoked later" thread for a slight perceived
     * performance boost.
     */
    public void resizeDesktop() {
        SwingUtilities.invokeLater(new Runnable() {
                public void run() {
                    // has to go through all the internal frames now and make sure none
                    // off screen, and if so, add those scroll bars!
                    Rectangle viewP = getViewport().getViewRect();

                    int maxX = viewP.width + viewP.x;
                    int maxY = viewP.height + viewP.y;
                    int minX = viewP.x;
                    int minY = viewP.y;

                    // determine the min/max extents of all internal frames
                    JInternalFrame f = null;
                    JInternalFrame[] frames = getAllFrames();

                    for (int i = 0; i < frames.length; i++) {
                        f = frames[i];

                        if (f.getX() < minX) { // get minimum X
                            minX = f.getX();
                        }

                        if ((f.getX() + f.getWidth()) > maxX) {
                            maxX = f.getX() + f.getWidth();
                        }

                        if (f.getY() < minY) { // get minimum Y
                            minY = f.getY();
                        }

                        if ((f.getY() + f.getHeight()) > maxY) {
                            maxY = f.getY() + f.getHeight();
                        }
                    }

                    setVisible(false); // don't update the viewport while we move 

                    // everything (otherwise desktop looks 'bouncy')
                    if ((minX != 0) || (minY != 0)) {
                        // have to scroll it to the right or up the amount that it's off screen...
                        // before scroll, move every component to the right / down by that amount
                        for (int i = 0; i < frames.length; i++) {
                            f = frames[i];
                            f.setLocation(f.getX() - minX, f.getY() - minY);
                        }

                        // have to scroll (set the viewport) to the right or up the amount 
                        // that it's off screen...
                        JViewport view = getViewport();
                        view.setViewSize(new Dimension((maxX - minX),
                                (maxY - minY)));
                        view.setViewPosition(new Point((viewP.x - minX),
                                (viewP.y - minY)));
                        setViewport(view);
                    }

                    // resize the desktop
                    setDesktopSize(new Dimension(maxX - minX, maxY - minY));

                    setVisible(true); // update the viewport again
                }
            });
    }

    /**
     * propogates removeAssociatedComponents to DesktopMediator
     *
     * @param f the internal frame whose associated components are
     *   to be removed
     */
    public void removeAssociatedComponents(JScrollInternalFrame f) {
        desktopMediator.removeAssociatedComponents(f);
    }
}
